Why unofficial user repositories

Since the AUR only allows users to upload PKGBUILD and other package build related files, but does not provide a means for distributing a binary package, a user may want to create a binary repository of their packages elsewhere.

However: Be advised, if you only put your packages in your private repo and neglect AUR, your package will never make it into community repo nor a central storage space(AUR) which is bad for users, since they will have to add 'YetAnotherThird-party-Repo'(YATR) to their /etc/pacman.conf which will make it slower to update. But the main reason you should not have repo-only packages is that not having packages in a central place confuses and gives users a second job in that they now have to search for Repositories in addition to Packages.

Thus the best way to have a private repo is to offer it as a supplement to the AUR for those users who don't want to compile. You should try to avoid to offer it as a substitute.

The future of Unofficial repos

I'd like to see more work of this type. Sometimes there are certain projects that don't mesh well with other things, such as the community repo. The 'kdemod' project is a good example.

In the future, well-thought-out user repositories may be ideal for lots of supplementary things. Forming a "web of trust" is important in cases like this, so we may begin keeping a list of "recommended" repositories somewhere, in order to make it seem more official and trustworthy.